1. Field of the Invention
The present invention relates to devices for cleaning laundry, and more particularly, to a device for use in water for cleaning laundry without the use of detergents.
2. Description of the Background Art
Laundering of clothes and other fabrics to remove soil and other common contaminants is well known in the art, and is a part of daily living in many parts of the world. Prior to the mid twentieth century home laundering was a laborious task, usually consuming an entire day of work. Since World War II, however, great strides have been made in the convenience of home washing. The automatic washer and dryer revolutionized the chore of home laundering. Consequently, heating water to fill the washer, using the washer and wringer, and hanging linen and clothing to dry have become obsolete with the home laundering equipment now available. By merely loading clothes in a washing machine and adding detergent, the modern home machine automatically puts the clothes through a suds cycle and one or two rinse cycles. Thus, a person is freed to do other things while the wash is being done, and, instead of hanging the clothes to dry, a person can now remove them from the washer and quickly dry them in a dryer.
In the middle ages, soap was made at home and used for cleaning laundry. Cake soap, however, was a luxury product that came into common use only in the 19th century. The synthetic relatives of soap, detergents were developed during World War II when the natural ingredients for soap became scarce. Unlike soap, detergents are synthetics and do not form easily biodegradable waste products.
By the 1950's detergents had become more popular than soap for general laundering and dish washing since soap, when used in hard water (i.e. water that contains a large amount of dissolved mineral salts), reacts, unlike detergents, with the dissolved salts to form a whitish gray precipitate responsible for the common bathtub ring.
Sodium sulfonates make up the most common group of detergents. Sodium alkylbenzene sulfonate, or sodium ABS, was one of the earliest detergents. Its molecules comprise a long chain of hydrocarbons formed by linked carbon atoms having two hydrogen atoms attached to each carbon atom. The chain is not straight: the carbon atoms branch off at one end. This is the hydrophobic part that attaches to soil. Attachment to the soil is facilitated by the ionic attraction between the positively charged soil particles and the negatively charged hydrophobic end of the molecule. At the other end, a sodium sulfonate molecule attaches to water.
The detergents used for washing clothing also typically include a number of additives--for example, bleaches, brighteners, and abrasives. Bleaches whiten fabrics by destroying dirt and colors. Brighteners are chemicals that convert normally invisible ultraviolet light into visible light, such that additional light reflects back from the fabric, making it seem more vivid, or "whiter." Abrasives are ground-up particles of sand or other rock minerals added to detergents to scour stains.
The basic cleaning agents in detergents are called surface-active agents, or surfactants. When added to liquid, they reduce the liquids surface tension (the affinity that the liquid's surface molecules have for each other), thereby increasing the liquid's spreading and wetting properties. Part of the surface-active molecule is hydrophilic, or "water loving," and another part is hydrophobic, or water-repellant.
The seemingly simple action of cleaning a soiled surface is actually a complex four-step process. First, the surface to be cleaned is made wet. Soaps and detergents help the water spread out and wet the surface by penetrating the fabric fibers. Second, the surface absorbs the soap or detergent. The hydrophilic part of the surface-active molecule attaches itself to the water, and the hydrophobic part attaches itself to the solid or fiber, and most important, to the soil. In the third step, the soil is broken up into small beads that can be washed away. Mechanical agitation helps the surface-active molecules pull the dirt away from the material and into the water. Finally, the dirt is rinsed away in the water.
There are, however, a number of disadvantages with prior art laundering methods which rely on detergents. Namely, detergents used for washing clothing typically include a number of chemicals and additives such as bleaches, brighteners, and abrasives, which, when drained into sanitary sewer systems, comprise pollutants. Accordingly, there exists a need for a substitute for detergents and the like which facilitates the cleaning of surfaces without introducing undesirable chemicals directly into the environment.